Publication Date:
2017-04-04
Description:
We present a model of seismogenesis on an extended 3-D fault, subject to the external perturbations
of coseismic stress changes due to an earthquake occurring on another fault (the causative
fault). As an application, we consider the spatio-temporal stress redistribution produced on the
Hvalhn´ukur fault by the MS 6.6 2000 June 17 mainshock in the South Iceland Seismic Zone
(SISZ). The latter is located nearly 64 kmfrom the causative fault and failed 26 s after the main
shock with an estimated magnitudeMw = 5.25 ± 0.25, providing an example of instantaneous
dynamic triggering. The stress perturbations are computed by means of a discrete wavenumber
and reflectivity code. The response of the perturbed fault is then analysed solving the truly
3-D, fully dynamic (or spontaneous) problem accounting for crustal stratification. In a previous
study, the response of the Hvalhn´ukur fault was analysed by using a spring–slider fault model
(SS fault model), comparing the estimated perturbed failure time with the observed origin
time. In addition to the perturbed failure time, this model can provide numerical estimates of
many other dynamic features of the triggered event, which can be compared with available
observations—the rupture history of the whole fault plane, its final extent and the seismic moment
of the induced event.We show the key differences existing between a mass–spring model
and this extended fault model; in particular, we show the essential role of the load exerted by
the neighbouring slipping points of the fault. By considering both rate- and state-dependent
laws and non-linear slip-dependent law, we show how the dynamics of the 26 s fault strongly
depend on the assumed constitutive law and initial stress conditions. In the case of rate- and
state-dependent friction laws, assuming an initial effective normal stress distribution that is
suitable for the SISZ and consistent with previously stated conditions of instantaneous dynamic
triggering of the Hvalhn´ukur fault, we obtain results in general agreement with observations.
Description:
Published
Description:
906 - 921
Description:
3.3. Geodinamica e struttura dell'interno della Terra
Description:
JCR Journal
Description:
reserved
Keywords:
Dynamic triggering
;
04. Solid Earth::04.06. Seismology::04.06.02. Earthquake interactions and probability
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
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